/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.commons.security.encrypt;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.lang.reflect.InvocationTargetException;

public class AsymmetricEncryptFactory {
    private static final Logger LOGGER = LoggerFactory.getLogger(AsymmetricEncryptFactory.class);

    private static volatile AsymmetricEncrypt asymmetricEncrypt;

    /**
     * load encrypt provider class for encrypt or decrypt password
     *
     * @param providerClassName encrypt class name
     * @param providerParameter provider parameter
     * @return AsymmetricEncrypt instance
     */
    public static AsymmetricEncrypt getEncryptProvider(
            String providerClassName, String providerParameter) {
        if (asymmetricEncrypt == null) {
            synchronized (AsymmetricEncrypt.class) {
                if (asymmetricEncrypt == null) {

                    try {
                        Class providerClass =
                                getClassLoaderForClass(AsymmetricEncrypt.class).loadClass(providerClassName);
                        asymmetricEncrypt =
                                (AsymmetricEncrypt) providerClass.getDeclaredConstructor().newInstance();
                        asymmetricEncrypt.init(providerParameter);
                    } catch (ClassNotFoundException
                            | NoSuchMethodException
                            | InstantiationException
                            | IllegalAccessException
                            | InvocationTargetException e) {
                        LOGGER.error("Failed to load encryption class", e);
                        throw new EncryptDecryptException(e);
                    }
                }
            }
        }
        return asymmetricEncrypt;
    }

    private static ClassLoader getClassLoaderForClass(Class<?> c) {
        ClassLoader cl = Thread.currentThread().getContextClassLoader();
        if (cl == null) {
            cl = c.getClassLoader();
        }
        if (cl == null) {
            cl = ClassLoader.getSystemClassLoader();
        }
        if (cl == null) {
            throw new EncryptDecryptException("A ClassLoader to load the class could not be determined.");
        }
        return cl;
    }
}
